In the above referenced patents, respective carrier designs are described. In U.S. Pat. No. 3,884,370, the carrier comprises a lower section having means for clamping one of the items to be transported and a T-shaped upper section having a spring-loaded clamp release lever protruding therefrom and connected to the clamping means in the lower section. In the carrier described and claimed in U.S. Pat. No. 3,960,264, the clamping means comprises a plurality of gripping levers so arranged that they are automatically adjustably movable as a result of the pendulum effect or tilt of the item being transported. This effect causes the item to move into a tighter engaging position in the carrier with each tilt or swing. Release means are coupled to said levers for removing the item therefrom.
While the foregoing carrier concepts are quite sound and have been demonstrated to work effectively in mail processing applications, they have a common major shortcoming. That is, they require an excessive amount of physical space or volume to store a large quantity of documents. This condition limits the size of systems that can be configured utilizing these carrier concepts. The methods used to clamp and release documents from these carriers account in large measure for the space occupied thereby.
By way of example, the carrier described in the reference U.S. Pat. No. 3,960,264 is approximately 1.125 inches thick in the direction of travel and storage. On the other hand, its maximum document thickness handling capability is only 0.5 inches. Therefore, its storage efficiency in this case is 44 percent. The problem of wasted storage space becomes even more evident when the carrier transports a document having an average thickness of 0.150 inches. The storage efficiency falls to 13 percent.
The carrier of the present invention eliminates the aforementioned poor storage volume efficiency and is therefore especially useful for large scale applications.